Analytical studies of collimated winds. II  Topologies of 2D helicoidal MHD solutions
Abstract
Analytic solutions of the MHD equations are given for magnetized outflows from a gravitating central object that are steady, rotating, nonspherically symmetric and helically collimated. The heating/cooling and temperature distribution is developed for helicoidal geometries, and the polytropic equation of state is then considered in a less restrictive form. A polytropic relationship between pressure and density is confirmed when a variable index is applied. The rotation, collimation, and magneticfield strength are varied to examine the solutions when the latitudinal extent of the polar conical flow and critical points are given. The outflow is more bipolar when the magnetic component dominates the hydrodynamic component, and the asymptotic radial speed is greater in magnetized outflows and increases logarithmically. The ramifications of the findings are discussed in relation to astrophysical systems including coronal hole/helmet structures.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 September 1991
 Bibcode:
 1991A&A...249..156T
 Keywords:

 Helical Flow;
 Magnetohydrodynamic Flow;
 Stellar Winds;
 Topology;
 Two Dimensional Flow;
 Collimation;
 Gravitational Effects;
 Rotating Fluids;
 Steady Flow;
 Astrophysics